Arc 4478/impl 4781 remove rudder rule variables

This PR must be merged after https://github.com/Normation/rudder/pull/500. 

This PR do some refactoring and remove the use of ${rudder.ruleId...} variable. 

The main refactoring points are:
- use Map[NodeId, NodeInfo] to change find by get
- remove lookupRuleParameterization and its call sites
- change the way buildNodeConfigurations are built to make the process based on immutable datas

In itselve, it does not gain much speed, but it allows to do https://github.com/Normation/rudder/pull/507 which brings a 10x improvment.